Trunk-selecting switch.



i 1. Emcxsow. RuNKELEcmSWITCH.. 'APPLICATIONIILED JULY M1913.

5 SHEETS-SHEET l.

um w,

, mmm Junges, 1916.

'IIERICKSOM TRUNK SELECTING SWITCH.

APPLICATION FILED JULY 7* I9'I 3.

Patented June I5, T916. `5 sHEETss.HEET 3.

am IH 1. ERICKSON. I

' vTRUNK SELECTING SWITCH.

APPLICATION mfp uLY, 1913.

1 ,41 86,47 1 Y Patenti-ed June 6, 1916l SHEETS-safer 4.

, hummm? WWA/55555 y W #Jfm J. ERIG'KSQN.

TRUNK SELECTING SWITCH.

APPLICATION FILED JULY?, X913.

1,186,431, Filmmaking-6, 1916. 5 cMFE'YS-bHE' JL @D llllllllllillll Tram/5X5.

UNITED ,sTATEs PATENT JOI-IN ERICKSON, OF CHICAGO, ILLINOIS, ASSIGNOR TO AUTOMATIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

TRUNK-SELECTIN'G SWITCH Specication of Letters Patent.

Patented June 6, 1916.

Appiiation flied July 7, 1913. serial No. 777,675.

.Tof/ZZ 'whom it 'm (1 7/ concern:

Be it known that I', JOHN ERICKSON, a citizen of the United States of America, and

resident of. Chicago, Cook county, Illinois, have invented a certain new and useful Im- `p'rovement'in Trunk-Selecting Switches, of which the 'following is a specification.

My invention lrelates to improvements in trunk-selecting switches, and more particularly 'to a non-.numerical trunking switch provided with line wipers which are moved to and fro over a series of trunk terminals for the purpose of selecting, an idle trunk.

It relates to a switch of the type in which the line wipers are normally in contact with the last trunkterminal employed by that switch, which wipers,pass oft' this contact,

' 'when the next call is made only in case this contact is busy. .Heretotora in switches of this type, the wipers 'werf rotatedv .continul ou'sly.

The object of 'my invention', however, is'

to provide a'switch of this character in 1 which the wipers move .back and forth from v the other and select trunks in both trunks when moving in one direction only.

'of John and Charles J. Erickson,

MY provenient upon the co-pending application Serial No. 379,18?, led October 16,' 1905,- 1n which there is shownha master switch for 'con trolling the 'nonlnumerical tru'nkfselecting switches, i.

A further Objectis separate seriesl of trunk terminals, 'the wipers Ofthetriinkin'g switch contacting with one series during movement .in one di rection and contacting with the trunk 'ter minals ofthe second series during movement in the opposite direction, whereby the switch has access. to twice as many l there are trunk terminals in asingle row. f

trunk lines as A further'object of my'invention isthe -provision of improved. means for shuntin'g lhesprings of the interrupter mag'netbya condenserto reduce ,the spark-ingl at the contact springs. Ordinarily-'a Vsepa-'rate con-v denser liasbeenv employed for each interrupinvention is also in the nature of an im-V right side knownftyp .the provision of two ter magnet. By my present. invention, however, a single condenser is socoiinected that A it is used n common by ,a plurality of vswitches, 'thi condenser being momentarilyconnected L w th the interrupter magnet, of' these switch@ when that particular switch is operated.

, i l ,These and otherobjectsy oii mjy-invention will be more clearly understood by referring' to the accompanying draifvings,in which I have illustrated my improved line switch in connection with a complete .automatic system of a well-known type..

The selector 'and connector switches shown and described are well knownin the art, and I do not in any way, wish to 1 limit liny-invention to use in connection with the particular type of system illustrated.

'In the accompanying drawings'Figure 1 vis a diagrammatic ylayoutof an automatic `telephone systemV in which I'have. chosen to illustratemy invention. Fig. 2 is' a 4front elevation `of an automatic trunk-selecting' switch embodying the principles of my in vention'. '.Fig. 3 is a side v ew, of the same with the side plate 3 (Fig. 2) removed. Fig.

4; is-'a detail sectional view on the yline 4.--4'

in Fig. 2. Fig'. 5 is a detail sectional view on n the line 5--5 in Fig. 4. Figs. G and 7 show a complete connection betweenfa calling tele-- phone T and a called telephone T. in the system represented in Fig. 1. Fig. 8 is a front elevation' of 4a'niodified forni of the switch shown in Figs.. 2 and 3. Fig. 9 is a left side view with theside plate removed.

. The telephone Sysam` shown in Fig.4 1 is teljephbri'ev exchange' of a well an automat c d o mp'iyisngf subscribers individual switches C, so-called first selectors D, second selectors .E and connector switches F.

In the drawing there is represented, on aj view of the same with the side plate removed. Fig. 10 -is a fragmentary scale of three to ten, three thousands of an exchange of ten thousand line capaity.- The vsubstatidii T and the lines cennected thereto are divided intol groups T2, 3 and T*,etc-f, usually ,ofoiie hundred lines each. On a scale of three toten, therefore, the groups i T?, T3, and T* represent one complete thousandand the groups T, T, and T1 represent another thousand, etc. With each group of subscribers lines there is associated in'ftlfile r central otlice a group of individual or line switches C, one 'for each line, a group yotfrst 1 selector switches D, group of second selectors and a group of connector switches F. The selector and connector switches represented herein"-cgiuprise banks of contacts arranged in lidiizontal rows or levels,

'usually lten in number. The levels are represented diagrammatically by horizontal lines .which extend across a group of switches, thereby indicating that-the correetc. vAll the second selectors associated with L a given thousand are inultipled together'and spending. contacts of all the switches ofthe, group are multipled together. All the line switches C belonging to a single group of` subscribers lines have common access to a group vof first selectors D. The bank contacts of all the first selector-sof correspond' ing hundreds are multipled throughoutwthe different'tho'usands. The bank contacts of the firstl level of these first selectors are con- .nected to trunk lines leading to second l,selec- 2o tors associated with the first thousand, the

contacts of thesecond level are connected to' the trunk lines leading to the second selectors E associated with the-,second thousand,

the lirst'level is connected totrunk lines leading' to connectors which have accessto the lines ofthe first .hundred 'group of. .that

thousand. The second'le'vel'of the second selectors 'is connected to trunk lines leading y'to connectors'having .access to the lines of the second hundred ofthe thousand, etc. This trunlng arrangement of an automatic j exchangefisgenerally well known-and eX-v. 'jplanation in greater detaill is not thought erstelephone T connected to conductors ter- .rnfinating 4at the central office in an individual or line switch C similar tol that shown in Figs. 2and 3. By means of wipers?, 8 and r9', and 7, 8a and 9, together with a bank of l tion of the calling subscribers to a first se- Y common access to trunks leading to the above-mentioned selectors, 'which 1n -turnl have laccess to other ltrunk lmes leadmg to contacts, .thisswitch 'extends the line conneclector D.` A number of line switches C have second selectors E. rlvhe 'second selector' E with which the subscriber obtains connection extends the line connection to a connec-` tor switch F, bymeans'of which, connection 'may be completed with the subscribers lines.. Associated with the-connector F 1s a ringing erator R .and a busy' s1gnal1ng machine.

g@ H." `Current for the purpose of operatlng -Before describing the. complete operation of the system as a` whole, a detailed descrip- `tion will be given of the construction and .sa

mode v of operation ofthe lswitch shown secured between two plates 2 and 3 (Fig. 2) this bank comprising two setsof contacts 10 and 10a, and two sets'of'ivipers 7,8 and 9 and 7a, 8a. and 9a are provided for-wiping over and making contact. withthese con- The shaft 29 is adapted -to be oscillated through a .portion of a. revolution so as to carry the wipers back and forth over their' v respective rows of contacts. The two 'sets of wipers are so arranged that only one set is in engagement with the vcontacts at a time and the shaft. is adapted to be shifted end-` wise at each end of its travel, so as to move. one set of wipers out of engagement with'its contacts and the other set into vengagement with its contacts. The contacts are'suitably mountedand insulated. between two plates 25 and 26, which in turn are held in place-by means-of two posts 27 'and 28 clamped between the plates, 2 and 3. Thev complete bank of contacts is readily removed from the switch by turning the 4post 28 aroundy until the fiat-portion 28 of the post is facing -the edge of `theplates 25 Aandl 26, thereby taking away the means -ofl support from this end ofthe bank. The bank is then drawn o f the postg27. The .means' for oscillating the wipers over the bank contacts comprise Figs 2, 3, 4 and 5. A bank of contacts-is lml -tacts'. These-wipers are mounted on a shaft y 29journaled between .the plates 2 and 3.

anelectromagnet 6 withits armature 30,:the

pawl'l andratchet wheel 324. The-ratchet wheel 32fissecured to they shaft 33 ori-which 36 which engages a gear segment on the` to be energized and denergized a number o-f times insuccession, the wheel 32 and shaftl 33' maybe rotatedfin a step bystep manner in a clockwisedirection, as shown in Figs. 3 and 4. During the frst half of the revolution the segment 34 willengage the vvupper .isadapted to lengagewith .one or the other of the .toothed'portions of'a double rack, i which is slidably mounted on the plateq2.

Secured to the double'rack there is a rack l 10,5v lwiper shaft 29. By-'causing the magnet 6I set of teeth inl the rack 35 and move said rack, A

together with the rack 36, to the right, thereby rotating the. shaft 29 in a-clockwise direction. During the second half 'of the. revolution of the shaft 33, the gear segment 34 p. engages. thelower teeth of the rack 35 and moves said rack andv the rack 36-backto wardithe left, whereby the shaft 29 is rotated in the opposite or counter-clockwise direction. Thus'it is seen that by continuously energizing and denerg'izing the mag- A.net 6, thewipers of the. switch are caused' to rotate .back and forth in a--step by step manner from one'fend tothe other oftheir rows of contacts. 'A detent 49 (Figi'lfis. f

provided for--preventingah backward rota'- tion of the" ratchet wheel 32. Thereis also provided an 'additionalis-.toothed wheel 50 130i' `is engaged by a detent 51 on the armature 3,0 each time said armature is drawn down "by the energization of the magnet 6. v-This is to prevent the wipers from rotating more thanone step at a time. The armature is attracted against thetension of the spring Q55, by means of which said armature is 'returned to normal position when the magnet 6 denergzes.

.The manner in which the wipers are shifted from one set of/ contacts to the other at the end of .therows is as follows: In Figs. 4 and 5 there are shown two springs 38 and 39 which are adapted to engage the op'- posite sides offa cam 40 on the shaft 29. The inner ends of these springsrest upon a Vstationary lug 41. When the shaft is in the position shown in Figs. 2, 3, 4 and -fthat is, whenthe wipers rest on the last contact at'the right-hand end of their rows--the shaft is held by the spring 39 inits upper position, as shown in Fig. Q-that is, in its lowerposition, as shown in Fig. 5.v In this position the wipers 7,8 and 9 are in engagement with their respective rows of contacts andthe wipers 7a, 8,- and 9? arelifted off their contacts. Assume now that'the shaft 29. is` rotated in a clockwise direction, as shown in Figs. `3 and 4. During this move` ment ofthe-shaft the cam 40 moves ina clockwise direction, as shown in Figs. 4 and 5j, passing beneath the lug 4l. As the shaft continues its rotation, the cam 40 passes between the lug 41 andthe spring 38. The lug 41 prevents the shaft from moving upward, and consequently the spring 38 is forced downward until the wipers reach the last contact, when the spring 38 will have been depressed considerably from its normal position. lVhen the wipers make their last step in this direction, the right-hand end of the cam 40 passes beyond the Vleft-hand end ofthe. lug 41, so that the spring 38 is then able to shift the shaft endwi'se until the cam LLO-coines above the plane of the lug 41. In

v turn movement', the cam 40 passes along the i interrupter springs 55, 56, 57 and 57a. The

top of the lug 41 andV underneath the spring -39 until it reaches the end of its travel,

when it passes the lug 41, and the spring 39 is then free to shift the shaft back to its original position.

The magnet 6 is provided with a set of spring57- is curved on'the en d, so as toengage the underside of the spring 55and the upper side of spring 56. This spring has a slight downward tension, but this 1s normallv overcome bv the greater tension ofthe spring 56, so that the threesprings 56, 57 and 55 arefnormallydn electrlcal engagep with the spring 56. The thumb screw 5S in the arm 59 forms a means of adjusting the spring 55. The switch is also provided with two relays 4 and 5 which control two groups of contact springs through the medium of the respective armatures 21 and Pivotally mounted on a plate above the coils of the relays 4 and 5f'there' is a bell crank lever 46, one end of which engages a lug Q2 on the armature 22 of the relay 5, while the other end is provided with a notch which ylies in the path of the upwardly extending arm of the armature 21 ofthe relay 4. This end 4of theI lever-46 normally forms an obstruction for the armature 21, so thatit can be attracted only far enough to break the back contacts of the relay springs and not farl enough to close the front contacts.

. Vhen the relay 5 is energized, its armature the line relay and the relay 4 the cut-oft1 relay.v The corresponding wipers?" and 7, 8 and 8a, and 9 andQv are electrically connected togetherv and the two sets of contacts 10 and 10a (Fig. 2') form terminals of separate trunlclines, and thus it is -seen that the switch" wipers engage different 'trunk lines when traveling in one'direction'froin those which they engage when traveling in the other direction, so that the total number of trunk lines to which the switch has accessis twice as ygreat as the number of contacts in one row. The switches C, as shown herein, are individual to the subscribers lines and thel bank contacts of a plurality of these switches are multipled together and lead to a common group of first selectors D.

At 300 there is shown a condenser which is common to a plurality of switches C, the purpose of which is lto prevent. excessive .sparking at the interrupter contacts of the magnet 6. Themanner in which ythis is accomplished will be explained later.

.The substation T may be 0f any suitable common battery type. As shown herein, it 13o comprises the -usual receiyer;11,1"tr'ansmitter 12, switch 'hook 13, ringer 14:: anfde'ondenser' 15.- Being an automatic substation, it'is also l.provided With the impulse springsl land 17. Y.

' and impulse Wheel 1 8.A The impulse. wheel'carries upon'its peri herythe impulse' teeth '194and'fis secured of a'sha'ftfQO, `to

Iwhich'V latter Lthere isy also attached laldial '(not shown) provided. with finger holes `through the .medium ofwhich the impulse Wheel may be rotated. "As the impulse wheel Letters Patent'No.- 81'5321, gra-nte`d March l3,"1906, tofKeith, Erickson and Erickson,

' being modified, however, ltooperatein a two- 'Wire system.` It'compr1ses,'an1ong other details, Va'seto" Wipers 6G-[61 and 62 carried upon 'a sha-ft (no tjshoivn) which' has a vertica l mot-ion `controlled.by-"a magneto?) and a rotary -mo'tionc'ontrolled 'a magnet' 64e. The usual side switch'coniprlsing the Wipers A65 and 66 is" controlled'by the private magnet 67 inV a -WelllrnownnmannergfFor .the

'purposeof restoring the switfchto itsnormal posit-1on,-there 1s provided. a releasen'iagnet l 6 8 .which restores' the' switch 'immediately 'u pon'energizing, ratherthan upon deener-v giziiig as shown inthe selectorgpatent re- -er'redt'o above. Aldoublevoundj line relay f6.9 vis, connected to the line relays 96 and 103'are slow acting-that is,

. slowrtodenergize after their' circuits are details, the usual' nets' 7 1 and72, the l1 rela.l 74, release magnet 75,"rlng1ng relay broken. .The secondvselector' 'E is lsimilar to the first 'selectorfll l 7 The connector s'witchFtEig. 7) is foffthe general typejof .switch disclosed in United States Letters Patent: No. 815,176, granted"y .March 13,51903; to -Keith,. Erickson and Erickson, being' modified, ho \ve\ 'er,;like the'.

selecto-11S', in Order t0, Operate-in a i'AVO-Wire system'.

vertical and rotary," g relay 73, back-bridge 76 and thefprivatemagnet 110.

Inl order to give a-clearer understanding of the invention, I. will', describe l,in detailhoiv"thesubscribenat the substation T may obtain "Connection'-fwvith the substation T.

le Will 'assume thenumber of the called substation'ito be 2220.@ In-the system shown herein, 'the subscribers lines are4 divided into groiuos anclfthe individual switches 'C of all theflinesfbelonging to thesame4 group have common access to the same group of..

selectors-.that is, each trunk. line. leading tothrough the springs of' the line-switching relay 70;; The

' 'The svyitcb comprises, among'other.

a first Selfetor, connected i in multiple'rto.,

the '-crrespondingfgbank' contact of' all the;

individualswitches of'zagrou ,"The

switches C shown'herein" doznot re ease" and return-'to normal.' position 'upon' v the 'termi'-v nation `or" a1conversat1o'n, 'I but .-jremain'j on the contact. oi .the trunlrl 'line .which wasflest 'used by the switch. "1`herefore,When-Ia.fsllbfscriber at.y thesub'stationx makes a '.GSJIL the Wipers ofthe switch. (3T-maybe standing on the contacts of; a busy trunk, {o -on' thel contacts offan idle trunk. .the wipeisare standing on .the contacts; Qf an' .idle .trunk when the subscriber at, the substation makes a ,call,; they remain stationary ,andthe'f-relay 4 'operates i to. connect .the line" through '"-tov vthe first 'selector DIy If .-thetrunkupon which the-Wipers are. standing' is busy', .they 4ivil'l be rotated to'an idle trunk--before4 .the .'line is connected with them. ff v.When 'thesubscriber at the `substation I removes his receiver'4 from the switch hook preparatory to making a' call, fthe' er,igagement` of' the.

hook 4switch springs S'Oj'andlwcloses av cir-j.-`

cuit through the linerelayl gfo :thefswitch 1C, said circuit extending'Tf1- om groundf'Gf through the back-'contactof thespring82, conductor S3, `through' the subscribe1".s tele? phone', back, over the conductorl 84e,4 lthrough the 'back' contact'v of. the spring-"85' and through the relay 5 Ato thev batterylead 10Q. The! relay 5,.' upon energizing, completes .a circuit extending l from g'roundfGr2 through the"c'o ntacts of the springs'SG, relay 4, in-

4t'errupter :springs 55, 56. and 5 7, through the 'lnotorfmagnet 6 to lthe .battery lead `100,

.thencefthrough'the-battery 'BA tofground G;

If the-'Wipers of the svitch C are standing on an' idle trunk, the closure of vthis circuit causes, the relay al to be energizedybutthe loo resistance] of this relay fis high enou gh t'og.

prevent sufficient current to flowthrougli the magnet v6 to-c'au's'e vit' tobe operated. HoWever',-'i-f the .Wipers are resting on labusy trunk line, i the Wiper 9 willv -b'e grounded', Therefqre, fwhen'l 'the relay 5 energizes, 'the relay" 4".ivillf-not be. energized,I 'owing -to 'a slic` rt circu itl extending from 'the E grounded contact onivhi'ch the Wiper 9 is standing, through 'said' Wiper., `back "contact,- of, the

spring' 88,1', springs'89 '.of `the lrlelay5 and through the' relay e', and springs "-86 f to.` ground G25; Upon' the 'sho'rt-circui'tingj'-of the. relay-.11, the magnet Sis-allowedr to pull up to advance the-"Wipers ofthe yswitch onestep and to'interrupt its own circuitat the springsf, 5G and 57. If'the next trunk is .also busy, the motor -I'nagne't 6'Will 'be again energized manner.

In. fact,f the 'opera-tion is repeated',

the Wipers reach -lan idle trunkv line lthel relay 4: Vceases t0 -be 4sh0` `rt`'circiuted and 'its armature-"is attracted the circuit being traced' above;

Aim'

to advance the Wipers in the `same "until 'an idle'trunk V'is.1ea"ched As soon'as' lVVheIr the 'relay 4l energzes, there!) springs .82 and 85 break contactwith ,their back contacts and make contact with their front contacts, thus disconnecting ground lr and the line relay 5 from the calling line and extending the line connection through the wipers 7, 8 and 9 to a first selector D. y Wlien the connection is thus eX- tended, the line relay 69 becomes energized over a circuit extending. from vground G3- through the 'lower winding ofthe relay 69, backcontact of the spring 89, line wiper 8,

` front contact of the spring S2, conductor83,

through the. telephone at the substation T,

back over the conductor 84, front contact of the spring S5, line wiper 7, vback Contact of l the spring 90 and through the upper winding of the relay 69 to the battery lead 1'00. The' relay* 69, upon energizing, completes a i circuit from ground G4 through the .front contact ofthe spring 95and slow acting relay 96 .to the battery lead 100. The relay 96, upon energlzing, extends a guarding potential from ground through the springs `ergized when the relay -5-denergizes 97 to the private bank contacts of the trunk leading to the selector D in all the indithrough the front contact of the spring 88d.

Each time the magnet 6 is energized, the

condenser 300 is shunted around said-inag net and its interrupter springs at the instant thecircuit of the magnet is broken, so

as to provide an inductive shunt across theV contactsv to prevent excessive arcingwhen the circuit is broken. The condenser is sliunted aroundV the magnet by the engagement of the' spring 57a with the spring 56 just before the circuit of the magnet is broken at the springs 56 and 55. The armature of the n'i-ajgnet continues to move toward its core fora short v.distance after 'the circuit of the magnet is broken, so that finally the shunt through' the condenser 4is broken 'by the separation, of the springs 56 and 57..

Thus it is 4seen that the condenser is disconnected from the magnet either when the armature is inits normal position or when l it is fully attracted, so that notwithstanding the fact that the condenser' is common toa plurality Aof switches, the momentary connections of ground to the common terminal of the condenser by a.I magnet which is operating can have little'or no effect on the operation of any other magnet which is operatingv at the same time. 300 is preferably bridged by va high resistance 300a which furnishes a discharge path.

The condenser for it, but does not affect the operation ofthe switches.

The line relay 5 is slow acting, so as to maintainthc circuit of the relay 4 until after the relay 96 at the selector D has had time to 70 send back ground from ground G5. y

The above operations take `place upon the subscriber taking his receiver from the switchhook preparatory to making a call.

The subscriber now operates his dial in the usualnianner for the transmission ofthe first series of impulses for the digit 2. The contact ot' the impulse springs 16. and 17 is momentarily broken twice, thus breaking the circuit of the line relay 69 a correspondi go ing number of times. The relay `96 being slow acting does not have'time to denergize during the momentary interruption ofl its circuit by the relay 69. Each timethe armature of relay 69 drops back a circuit 85 is closed through the vertical magnet 63,

'said circuit extending from ground .G4t

through the back contact of the spring 95, front contact of the spring 102, slow acting relay `103 and through the vertical magnet 90 63 and side switchl wiper 66 to the battery lead `100.. Upon the vertical magnet being energized twice, the switch shaft is raised two steps. The relay 103is energized by the impulses passing through it and, being slow acting, retainsits armature until after the last impulse of theseries h as been transmitted. `In its energized position this relay closes the circuit of the private magnet'67.

4This circuit is broken when the relay 103 100 denergizes after the last impulse of the digit is transmitted and the private magnet, on denergizing, trips the side I,switch to second position in a well known manner. The side switch wiper `66, on passing to second posi'-v 105 tion, closes the circuit of the rotary magnet 64, which, through the medium of its interrupter springs, begins to operate in a manf ner similar to that of a buzzer to rotate the shaft wipers in search of an idle trunk line. 4Each time'the magnet 64 energizes, it closes the circuit of the private magnet 67 by way of the contact 64a. The magnet 67 energizes the first time this circuit is closed and remains energized untilthe first time the rotary magnet 64 denergizes, withl the private wiper resting on the contact of an idle'trunk line, at which time the private magnet deenergizes and the side switch passes to third position. The side switch wiper 66, 'oy pass- 120 ing from' second 'to third position, breaks the circuit of the rotary magnet and closes the circuitof the switching relay 70.' This circuit extends from ground G5 through the springs 97, relay 70 and side switch. wiper 125 6 6 to battery.- The relay 70, upon energizving, disconnects the line relay 69,v from the line and extends the connection to the sec-` ond selector E, whereupon the relays 698L and 96a become energized. The relay 96, 130

upon energizing, 'extends' a holding circuitbackjirom'g'round Gr8 through the relay 70 of 4switch D to maintain it energized laiter itsvoriginal circuit A is broken fby; the deeneiff gization of the "relay 96. 'lliesubscriber nowqoperates his dial for the second digit 2,

in response to whicli the switch-E operates the same. manner as explained for the switch to" .extend the connection 'to an idle connector 'l 4`," energ1z`ing'the line lrelay digit 2, whereupon the line relay is operated 'twice momentarily 'to energize' the vertical magnet 71,'tliereby`raising the switch shaft two -Jsteps and opposite' the row of contacts' in which is, situated thev terminalsl oi-the' called subscribers line.

t'rac'edffrom ground Gfjhbaclrcontact oi the spring. Y130, front Contact of the spring` 1 31,

.'vei'tical-niagnet'71, side switch .wiper 111 4'and slow act-ing relay"133 to battery. Upon -lt'he relay" 133 energizing, a c irc'uitfisclosed fromground G1? through the private inagv.net 110, which energizes to prepare. for

- the -escapenie'nt of. the :side switch' vto second position 'infl the usual manner.'

. side'switch wiper 111 passing to second. po'

sfition when' the relay 133 and the magnet S5- `digit .is delivered, battery current. is .trans- 11:0 d'energize after the last impulse "for the -fei'red from the vertical to the rotary mag#` .,ne't'72.'` The substation calling device .is now] '-.operatedl'for the last digit 0 and lthe contacts ofthe calledsubscribers line.

magnet 72, j.which rotates thewipers 123, 124 and 125 around ten steps onto the velentica-l magnet. 71,"beir'ig traced'froin ground G11 r'through.the-springs.130 and 1 31, .asor the magnet 71, thence througlrthe- Contact' of .the springs 150, rotary -magnet '72and* -fthrou-gh the side switch wiper' 111 andrelay "133 to battery B .u T he relay 133 andmagnet 110 operate as for the previous digit to cause the sidel switch to pass from' second to third position after' thelast impulse is f deliyered, Upon A thewipers and 121 reaching third position, the line connection is completed between theca'lling landfcalled lines. The side -switch 'wiper 122, lupon passing to' third position, places a' guarding.v

potential on all theprivate contacts in-1nultiple' with thevone on'` which the wiper 1 25 .is resting. This guardingv p'etentialv extends wiper 122, `contact of springs12'6aiidl pri# Upon the .nectorline relay 73 is de energzed ten' times, sendingten'. .impulses through. the rotary lcircuit .of the rot-ary magnet is very similar that described in connection` Vwith the'vervate. to saidbcontacts A jcircuit also' exte d-s from. the contact on whichtlie4 wiper '125` is resting through vthe relay 127,

contact of the interrupter springs 'of the magnet 128 andthrough said maghetto bat- ,teryf The h ig-lrresistance-.coil 127 --does not allow sufficient current to lpass' through the magnet 1281130 .operatively energize it.

The line'-1elay 129 d 0 es not .energize .when` the substation to which. itV belongs' is being called.` Therefore, when the armature of the relayv 127 is attracted, it :is only4 permitted by the armature ofthe relay 129 to pull up half the distance between its backand front contacts, tlius'cuttingout. of the line circuit-theline relay y129 and lat the samenl timenot connecting thev line to the-fwipeis of the. switch C". The side switch wiper -111, upon lpassing-to thirdl position, completes the'circuit ofringing relay-7 6 from groundv G2?, ringingjinterrupter 151,1con'- tact of the-.springs 152, relay 76, side switch wiper 111 and through therelay 133 to battery. The. relay 133l doesv not operatively y :energize inthis. circuit', .owing to theliigh;

resistanceof-:the ringing relay 76. lThev4 relay. 76"-i s intermittently1 energized and -denergized bymeans of the.. interrupter 151 to break thel connection between the 4'calling vand .called subscribers? lines and 'to'bridge' thefringing generator R across the line of the called 'subscriber to.ringtlielatter7s'bell.

Upon the Vcalled 'subscriber removing his :receivertoanswerthe call, afcircuit is closed through theback-bridge-'rela)7 474; at' the' springs 154, which, upon energizing, opensy the circuit ofthe ringing relay 76; ,thus preico venting further in t-erruptionv of the connec. 1

tion between the calling v and ealled lines.vv Hadtlie called .line' been busy, the side" switch would not have passed to third position, thus 'making the connection impossible, for a ground potential would .be on thegprivatecontact on whichl the `wiper 125 camel-tov fre'st.l Thisnbusy' circuit is well known inthe art and it 'isthought -unnecessary to trace itat this time. Uponv the coni- Y i-ie pletion ofgtlieconxersation, the central cniceapparatus is returned vto -normal by the Call-v ingl subscriber hanging-up his receiver, thus iisbreaki-ng the `.circuit 'of'the linerelay 73 in the connector switch'. This relayI de'e'nerf gi zes,' thereby breaking the circuit of the slow relay 106,.'wliich also vdenergizes, 4and .acircuit is closed from. ground G11 through the springs of the line relay 73 and slow relay'106, through the release magnet 75 Vand off-normal springs 155 Ito batteryfB. :The

release magnet energizes to 'return the-switch shaft to normal, at' which timethe circuit of springs v1525. Ground isfalso taken ofi the release trunk 156t upon vthe denergizationv of the-relays 73 and :106, thus 'destroying the vsaid/magnet is opened by the. shaft at the bf the switches E, D and C, respectively. In the case `of the relays 1 07 and '70 de'enerarising, the circuits of the release magnets 68a and GS are closed in 'a manner similar to that4 or' the release magnet 7 5 inthe connector. switchandthe lswitch shafts are returned to their normal positions. 1 Upon the relay si in the switch C denergizing, the line `connection'to the first selector is broken atthe springs ofsaidrelay andthe line re- -ilayis again bridged across the line of the substation fTfleaving the central otlice apparatus in a condition tov be used for an' other call.

' The switch illustrated in Figs. 8,9 and 10 is essentially the same in principle as theA ne-shownin Figs. 2, 3 and 4, with the eX- ception that the wipers 200, 201 and 202 os' Acillate o n the same contacts, unlike the wipers 7, 8 and 9, and'Ta, 8a'. andla illustrated in Figs. 2 and which latter, it will be remeinbered, are snapped o ver'from one-set of contacts-to another upon said wipers reaching the end of thearc. There'is also a dif-` ference in the driving. mechanism, while the springs. contacts, lmagnets and relays are the same. Eitherline switchis capable of takalso secured-to the-shaft 210 a notched segment 207 for the purpose of engaging with a retaining arm 208. This retaining arm is pivoted at .2141, and at its end is prov'ded with a bushing'216 which is pressed indi the notches ofLthe se mentg207 by pr sure eX- l f. erted bythe sprin i215 The pr sure on the vsegment 207 'issulicient to prevent the wipers 220,201and202from prematurely moving oil.

one of the contacts-209by ay possible jar.

. The pressure, however, is not enough' to retard theordinary operation of the wipers. Associated' with the ratchet wheels 203 and -204jis a double pawl 205 which is pivoted at 217 onthe armature 230. One end of the ".pawl `2O5fengages one ratchet wheel to rotate the wipers in one direction', while `the other wipers in the .opposite direction.

engages the other ratchet wheel to rotate the The respective teeth 'of the ratchet wheels are necessarily facing vin opposite directions,` as shown in' Figs. 9 and 10. Secured to the center of the pawl 205 is a grooved projection 220 for the. purpose of sliding between the guide springs 200, the function of which [.projection is to tilt the pawl one way or the other into engagement with one or the other of [the ratchet wheels. The springs 206 are` securely fastened between the plates 221 and 222 which are loosely mounted Aon one end of' lthe shaft 210. l The manner in which the pawl205 1s tilted is .as follows: When the wipers reachthel end of the row of contacts Iin one direction, one lor the other of the lugs 212 or 213 depending` on the way the wipers are traifeling) on the segment 207 strikes theilfo er end of the arm composed ot the plat `l- 221 and 222 and moves said arm slightlyin'the' same direction in which the. ie. are traveling. This causes the uppei .of lthe arm and the springs 206 to swing inthe opposite direction to turn the pawl 205 on its `pivot and reversethe position of the pawl 205, so that it now becomes operative to drive. the shaft in the opposite direction. In order to hold the arm composed ofthe plates 221 and 222 in either ofits positions, -there are provided at its lower end two locking dogs 224; and 2241L which are adapted to engage the lugs 227 and 228, respectively, .which project from theside plate. These lochingdogs are in the shape of bell crank levers pivoted between ,the plates 221 and 222,at their elbows. I One arm of eachof the levers extends down into the path of the lugs 2 13 and'212 on the 'segment 207, so that before either of these lugs strikestlie arm composed of the plates 221 and 222 it irst engages the locking dog and disengages it from its lug 227 or 228', as the case might be. A small spring 225 betweenthe dogs 224 vand 224ea serves te` bring them into engagement with their respective lugs when the arm is in the proper position. During the time when the wipers are rotating, the end yof the pawl 205 which is not doing the driving engages its ratchet wheel when the armature 230 is in its fully attract ed position, which prevents the wipers from being carried forward by their inertia after the armature 230 completes its stroke.

It will thus be seen that I have devised avery efficient form of lineswitch and one which is'accessible to twice as many trunk lines as has heretofore been possible in conby having the switch select motion on both the forward and back movement, there is no v*idle or lost movement. 1 YVhile I have illustrated my invention in connection with a Ifull automatic system, it is to be understood that my line switch can be employed in connection with any auto- 'matic'or semi-automatic system and in any position in which the line switches are eniployed. Various modifications in the struc- .tureof the switch itself will readily suggest themselves to those skilled in the art, but come withinA the contemplated scope of my invention.

vWhat I claim as my in vcntion is z- 1. In a telephone system, trunking switch,'t runk lines, said switch having line -wipers alwaysin electrical connection with 13b" some one,'of said trunks", which connected said switch ifor extendingfa call, andmeans for 'moving said switch lto 'and' fr o over `said trunk ,terminalsto select an-idle' t rl'1`nk.

if the connected trunkfis louSyfl 2. 'In atelephone system, -a trnnking switch, apln'rality of trunk" lines,s'aid switchhaving "switch *wiper-'s normal-ly :Contact witlio'ne offsaidtru'nk lines, lsaid -connected trunk vbeingy the lastonel employedbysaid., switch, .means for moving said switch" in one, direction. o v'er said.- trunks toV select an idle trnnkwhen the connected' trunk is-'bu'sy-,-

j andV means for reversing'- the .movement of fwhereb'y a ltalkingl circuit may lloe extended.

3,. In a telephone vsys rection. a'telephone system, a .trunk- Selectf ingswitch, A a'jseries of trunk terminals,l a

line .'wiper vfor said switch, an "operating magnet therefor, means for intermittently energifzingsaid magnet, 'andjmeans formoving said line Wiperfov'er said trunk-termi. nals in responsetda continued series of v'intermittent energizations of said magnet in either of two directions to lind anidle vtrunk through 'said Wiper,

5.- In 'a .telephone system, 'a non-numeri- Acall trunk-selecting switch, a plurality 'of series "oftrunk termin-als, line wiperncon# V dnct'ors for saidswitch, and-means' foros-: cillating said Vline condiu'tors, said :line conv-.- ductorsbeing in contact v Witli' one of said series 0f terminals during movementjin one direction. and fin 'conta ct'. with secon'd'series ofsai'd trunk terminalsdu-ringmoveL mentinthe opposite direction. 59f 6; In- --tele lione system, aV trunking'lv switch, ,a plurality of .series of trunk v. termi'- nals, said-switch -havingil'ine Wiper condiic tors? always in electrical connection with terminal of one of said ser-ies. which' connected terminal isal-Wa-ys the-last. 'one er'nl A I I lnect'edtrimk is busy.

ploye'd by said switch for Aexteridingf a calL- meansifo'r moving;r said conductors to and idle trunk if tlie connected trunk is busy,

. and means for moif'ing: said conductors finto' a position'to disengage from-said first se riesj and engage With-a' second .seriesof trunk' j for intermittently energizing Said magnet, Atelephone system; -a trunkingg vsw-itch,alplnrality of Series oftrunkermi? terminals;

...engage with one "of said .series of terminals during movement in 4 onex-direcrtion'- and e'n gage with i aj Second seriespff trunk -terninals during' movement -in the opposite rlireetic'n'l.A 18: Inf-ateleplionefsystmi..a ho'nmey said switchl and moving the -Sameinfthe op-"fAk posite' .direction bverfsaid `tru' nki=; to selectf idle trfnnks'whenfthe limit'ofvmovement of saidv switch is"reached` term; a trunk-selectf.- ing switch, lplurality o f. Series of 't-rlinkj termina-ls, line Wiper; conducto-rs' for. said"y switch, means fr-.oscillating said "condnctors, said conductors beinginf-contact with' one of saidseriesv offtenminalsfjdiiring movement in one, directionand inf-'contact "with-"a, 'sfecond series 'of said trunk ter'm', nals .'f'luring movement the oppositefdi-j' fro -oversaid 'trnnki terminals to select an "j nale-aia 'Sweetman-gunt wipefeonac- .tors 'always in electrical connection 't'.

' ployed: by said. swi h. forAv extending than,

mea'ns for moving 1saidconductors to andfrq- :ovjer' said trunk terminals to. SelectI an: idle trunk if the Connected tr'nk. .is busy,

means. for 4musing `'f-said' line conductors to-l cal trunk'i'ng.. switch., 'azplrality f. series' of' vwiperconductors- 'always in electrical con- 4ries 'and engage x'v'ith 'ag Secondwseries' of'.

.80 f-trunk terminals, said" switch having line Wiper .conductors always-'1in electricalcon` 'nals :to select' idleftrnnk 4if'thef connected series' o fterminals-dnring Ino'vnl'eli one direction and engage with .a .second senes I' of trunk 4terminals dnrlng: movement In the opposite direction,

energizing 'said magnet.4 and-"means vformoving said line Wipers .to and fro 'over said tru'nlz.terminalsin response to a 'continued Series ofinte 1 1n i-ttent energzations of said magnet' to select an' idle trunk 1f the conlIQIn a y telephone system.'y a trunking! switch,- a .plurality of trunk lines. said caltru'nkirig Switch, 'a nluralityiof-seriesoi leo les

switch havingswitch Wipers normally in .1725

Contact [with one of said tru'nk liiiesfsadf 'connected trunk being the last one employed bysald.l s\ v1tch.-. an operating magnet, means trunks to select an idle trunkrwhen the limit l insee-vi of said magnet for moving 'said switch wipers fin one direction over said trunk lines to 4select'an idle trunk whenthe connected trunk is busy and for then reversing the niovenieut'of vsaid wipers for n'ioving the saine in the -opposite direction over, said of movement of said switch is reached.

1Q. In a ltelephone system, a magnet proJ vided with interrupter springs, a condenser,

asliunt around said inagnetand springs including said condenser, and means controlled by the armature of shunt. f

13. In altelephoiie system, a magnet provided with interrupt-er springs, a condenser, a shunt-around' said magnet and-springs in- 4 cluding said condenser, means controlled the armature of said magnet-to' close said shunt, and means for opening said shunt when the armature reaches the limit of its stroke. v

14.. In a telephonesystem, a rotary trunk# selecting switch, an interrupter magnet controlling the rotation `of' said switch, said magnet provided with contact springs for Vconti-"olling the circuit of said magnet, a condenser, a shunt around said magnet and springs including said condenser, and' means lcontrolled by the operation of said'magnet to close said shunt.

15, I In a telephone system, a rotary trunk-- selecting switch, aninterrupter magnet controlling the rotationy of said f switch, said magnet provided vvithcontac't springs for controlling the' circuit of.said magnet, a condenser, a'shuntaround said magnet4 and springsincludingsaid condenser, means controlled by the operation 4of said magnet to yclose said shunt, and means for opening said 4 shunt when the armature reaches the limit of its stroke.

16.` In a telephone system, al non-numerical rotary trunk-selecting switch, an interrupter magnet controlling the rotation of said switch, saidmagnet provided With contact. springs for controlling the circuit of said magnet,'a condenser, a shunt around said magnet and springs including said .conI denser, and lmeans controlled bythe opera y tion of said magnet to close said shunt.

f 17. In a telephone system, a non-numerical 'rotary Vtrunk-selecting switch, an inter? rupter magnet controlling the rotation of said switch, said .magnetprovided with contact springs for controlling the circuit of saidmagnet, a condenser, a shunt around said `magnet and springs including said condenser, means controlled by the, operation Lof said magnet to. close said shunt, and

.means for opening said shunt When the armature-'reaches the limit of its stroke.

18. In a telephone system, a group of trunk-selecting switches, an operating 1nag.- net for eachswitch, contact-springs c onsaid magnet to close said ti'olled thereby. a condenser, a shunt around the contact sprnfigs of each magnet, each of said shunts iucluf'li-ng said condenser, and

means for intermittentlyclosing'y said shunt upon the 4 energization of said magnet.

19, In a telephone system, a plurality of traint-selecting switches, an interrupter inagneti'or each switchl provided 'withv contact springs for controlling the circuit thereof for controlling the rotation of each switch, a. condenser, a shunt around themagnet and springs of each switch, each of said shunts including said condenser, and means controlled by the operation of said magnet to close said shunt.v

:20.y In a telephone system, a-plurality of i trunk-selecting switches, an interruptei' magnetfor each switchprovided with contact springs for controlling the circuit thereof for controlling the rotation of eachswitch, a condenser., ya. shunt aroundthe'magnet andsprings of each switch, each of said shunts including said condenser, means controlled e by the operation of 'said magnet to close said shunt, and means for opening said shunt whenthe armature reaches the limit of its stroke.

21. In 4a telephone system, a trunk-selecting switch, a'series oftrunk terminals, a line wiper for said switch, an operatinginagnet therefor, means for'intermittently ener-w..

gizingsaid magnet, and means for moving said lin wiper to and fro over said trunk' termina in response tov a-continued, series of intermittent energizations of said mag-V 23. In av telephone system, a trunk. se-

lecting switch, a plurality of series of trunk terminals, line. 'wipers for said switch, and

` means 4for oscillating saidline wipers, means for holding some of said wipers in operative relation to the contacts ofone of said series when the 'wipers' are moved l'in one direction and for holding others of said wipers4 in operativevrelation to the contacts of another of said series'l when the wipers are moved iny another directien.

'24. In a telephone system, a non-numerical trunking switch, a plural-ity .of series of trunk terminals, line wipers fou said switch :normally in position to engage-with onefaf said series of trunk terminals and' to disengage with the other, and means for moving the disengaged wipers` into, and the engaged` talking circuit may be closed riesof trunk terminals.

wipers 'out of'engagement with. the termiv lflals.'v

25'.'-In a telephone-system, anon-numerr" lcal'trunk-selecting switch, a plurality of se- 5. ries ottrunk termmals, line wipers for said" switch, andine'ans for' oscillating some of said 4l1ne\v1pers means for holding sald wipers in operative relation tothe contacts of one of said series ".vhen the wipers are moved- 1n one dlrectlon and for 'hold-ing others in operative relation to the contacts.

of another of said series when' the 4wipers lare moved 1n another d11ect1on.

26. In a telephone s v'stem, a trunking A- switch, aplurality ofseries of 'trunk iter# -ni1nals,'s`aid swltch having line wipers' 1n electric'al connection witha terminal of one of said series, v'and -line wipers disengaged t 'from 'a terminal of oneof said series, saidvv by. said switch for extending a call, means. -or'movmg'said wipers to and iro over-sa1d` t'unk terminals to select an idle tru-nk if the 'connectedtrunkis busy, and means for-. 2 5 moving the disengagedwipers 'into engage? mentj with" said second .series of 'term1nals,

'm inals,said swi'tchthavingline wipers in electrical`- connection and wipers 'out of elec- -1 trica'l (:onnec t 1o n' y with a ternnnalof 'one of s'aidzserie's, saidfirst terminal always the last -i'-'one'e'mployed.by-'said switch for extending gall", means for 'moi-'ing said 'wipers toand'v -frofovefrsaid trunk-terminals to select an- "idle Vtrnlcif tlie-"connect'ed'trunk is'busy, ndfrneans for causing the second mentioned 49.-"line1wipers-to-- engage. with one ofv .said sevriesof terininalsadnring movement in one 4directic'on 'and the first mentioned line wipers r to fengagelwith :ase'cond series 'of trunk te1 minals during moyementm the lopposite d1= Alrection.

cal gtr'unking switch,` a plurality of series of trunk terminals, said switch having line..

i wipers'lin'electrifcal .connection with-a ter` "mi1 1al` of one of said series andwipers out `-'of{electrical connection with a terminal of a vsecond :of said series, said first terminal alway'sthe last one employed by said lswitch 'for extending a call,-mea ns'for movingsaid 55 wipers. to and fro' over said trunk terminals ft'o Select an'idle trunk ifthe connected trunk is`^busy,a nd means for moving the first menti'oned Vwipers into'A a position to 'disengage from' said first .series and the' second menf en tioned wipers to engage with saidsecond se- V 29. In a 'telephone system, a non-numericaltrunking switch, a plurallty of lser A'els-#of "trunk terminals, vsaid yswitch having line ai -wipers in electrical'onnection and wipers -cal trunk 'selecting switch, a plurality of lse- With'a-ny oneof the contacts and for moving. l 128,1 Ina telephone system', a non-numeri--- out' of. electrical connection with a terminal of one off ;`sa1di ser1es,p said first termlnal .always 'the last', oneemployed 4by said switch for extending call, means formovingr said- \v ipers'to and fro oversaid trunk terminals 70, to ,select 'an idle trunl if the' connected'trunl is busy, and means for'causing said second mentioned linewvipers toengage with one of 'said series of terminals during movement in' one direction land: the firstv mentioned line Wiperstojengage with a secon-d series' of trunk termina-1s' during movement in the opposite direction,

30. In a telephone system, a trunlr selecting sWit'ch,'a plurality of series of trunk 8o termi nals ,-a4 line wiper in said switchffor one of said series, another wiper for another one of said serles, means :for movlng one of said wipers along the4 terminals of one of said -s erles for stopp'fm'g -1t 1n engagement 85 with any one of the terminals', and for. moving the other of said wipers inthe oppositedireetion along the contacts of another one of said series and for-stopping. it in engagement with one'of the terminals whereby the'90 circuit maybe extended to theline through one ofsaid contacts.- jV

31 I'n a switch, afirst series of..line'te'r-' i mnals `ina plane,"a contact for engaging anyone of said'terminalS, a second' series', of 95 terminals in a plane, a contactfor engaging- V.any-'one of the terminals'in' the second series,-v mea'ns 4formoving said contacts 'in planes :parallel-to the plane ofns'ai'clfirst; series'an'd for moving them [in planes parallel tothe .10o .planeofthe-'second series, andzme'ansor 'moving siflfontat first tonne set-0f planes and then tothe other@ Bij- In a-t'elephon'e system, a non-numeriv'ries of trunk terminals, a line' wiper-fori eahof said series, means -fon movingfone'- of said wipers along the' contacts of one of said series and 4for stopping it inengagement' the other oneof. said wipers" in the opposite direction along the contacts of another one of said series-'and for stopping it engagement with anyone o f thecontacts.tol find an idle' trunk whereby a circuit may loel closed 1115 therethrough.y

33. "In" a' telephone system, a. non'`n1 1mer i cal ltrunkselecting switch, a plurallty of se1 'ies1 and fo1` vstoppingfit in contact with anyone of the' contacts and formoving another -one 4of. said' `wipers in theV opposite. di*- rection'along the .contacts of another one of saidscries -and 'for stopping it in CODaCt with any one of the contacts to find an idle Atrunkfwhereby .a circuitj may bev closed therethrough'and a connectionmafy be -e'xtended tothev trunk-and means orholding A -the Vwipers stationary until the connection is released.

y 3ft. In a telephone system, a trunk selectingswltch, a serles of trunk terminals, a hne to a` 'continued series offintermittent energij'oi zat-ions of said magnet in either of two .directions to find `:in-idle trui-1k wl'iereby a, conneoti'on may-be extended to the trunk, and

' means for holding the Wiper stationary until Qthe Vtrunk is released.,

1 5 i. 35.- In. a telephone system, a trunk selecting Switch,- a series of trunk terminals, a line l Wiper for said switch, an operating magnet' therefor, means for intermittently energizing said magnet, means for-moving said line l `wiper to and fro over said trunk termmals in response to acontinued series of intermittent energizations of said magnet to select trunks 1n both dlrections IY'vhereby a connection may be extended to the selected trunk, and means for holding the Wiper stationary until the connection is released.

3G. -In a telephone system, a. trunk selecting switch, ay plurality of series .of trunk terminals, line wipers 1n said switch for one of said series, another wiper for another of said series, a magnet for moying one of said wipers -along the contacts of one of said sey ries and for stopping it in Contact with any one of .the contacts and for moving theother .of saidhvipers inthe opposite direction along the contacts of another one of'said4 series and for stopping ,1t 1n contact with any one of the contacts therein, whereby a 4 circuit' may be ext-ended to a line therethrough.

Signed a JOHN ERICKSON. Witnesses i A. ANDERSEN,

G. YANocHowsKr.

g y by me Chicago, Cook county. -Illinois, this 28th day ofl June. 1913. 

